I believe this is already what we do. 361 posts + 22k views. And only one or two replies from Plex support… 
2020 bump - still having this issue.
+2 for 2020 bump, issue is worse than ever. Maybe devs will take notice when this gets a news slot for the longest running thread in history for a paid for product with no support. Guinness book of records?
BUMP 2020 - …
Come on Plex… You surely can get this resolved,
i had this issue but fixed it by going into settings on the xbox, and i believe there is a option for HDR and turning that off. its been about 2 months since i had it, but it was the only way to stop it from buffering like crazy
I wish this helped folks like myself that can’t even stream mediumish(8-10Mbit) quality 1080 content. I’ve had to forgo using my “HT” stuff and play through the built app for my Samdung tv. 
The lifetime pass was good for the time I have had it, but its clear that people should move on.
Get this fixed. I didn’t buy christmas passes for everyone because of this and other slimy ■■■■ Plex has been pulling for the last year or two. Streaming results in clients, Tidal and whatever the hell they called their curated podcast list - All shows that they care more about your eyes than your wallet.
Stop paying to be the object sold. They no longer value your current business, just your future value to their quarterly earnings report.
Are you guys using the server on windows, Linux or something else? I’ve never had issues on the original Xbox and I just pulled up a 10mbit movie, no buffering and I could jump to a random spot instantly.
Win10 x64, Ryzen 7 1700x, 32gb 3200Mhz ram, 1x500gb nvme ssd, 4x8tb hdds, gigabit lan. Each content folder is on a separate drive, plex app data folder is on one of the spinners because it’s quite large due to thumbnails for seek previews. It’s not a server problem, I can cast via app/laptop to Chromecast, I can stream to mobile on both lan and lte, I can stream across the globe, but can’t play mediumish 1080p to xbox on same lan.
I know that’s very much a run on sentence, the point is, the common denominator is the xbox client.
edited for clarity
Try disabling automatically scanning the library under server settings. I had buffer problems on roku ultra and fixed it by turning that off.
Same issues on my xbox1x. Plex please fix this or at least let us know what is being worked on to resolve it. I have enjoyed your product and paid for a lifetime plex pass like many of the other folks here, to support your product and future work. All I’m asking is for is to have some dialog on what I’d being done, and to know you are working towards a solution
same issue on my xbox one s
Bitstream audio was only fixed on ps4 after being broken for many months. Atmos is still busted for us. I’m not sure why console apps are neglected.
Same here, the issue seems to be the UWP app isn’t up to date with the server changes. (which would explain why some folks aren’t having trouble, thier servers aren’t on the latest version). This is extremely unlikely to be Microsoft’s fault.
Plex, feel free to reach out if you need help, seriously. I’ve been writing UWP media apps since day 1 and am willing to put a few hours in to help attach a debugger 
Same issues. Pathetic. Has been trash for a long time. Finally broke down and bought an ATV 4k.
It’s gotten so bad I’ve completely given up watching Plex on my Xbox One. I love Plex, but glaring issues being ignored like this is really frustrating.
Support is not just needed it’s essential at this point. Crossposted for the Reddit community who may miss this very important thread here
There are reports of Apple TV, PlayStation and Xbox issues now. I know each platform’s solution will be very different but let’s hope Xbox gets some love at this (multi-year issue) point.
Seriously this needs fixing now as the buffering is ridiculous… I have different devices throughout the household and the Xbox is the only one with issues so it’s no longer used. Come on FIX IT!